Battersea Power Station's chimneys may have to be completely rebuilt after a report revealed steel reinforcements used to build them are corroding.
Up to 9,000 jobs will be created at the complex
English Heritage is considering plans to rebuild the four chimneys on the south London site.
The Battersea Power Station Community Group said it wanted assurances the chimneys will be replaced.
Parkview, who is undertaking the £1.1bn redevelopment, said they would seek to replace the chimneys "like for like".
A statement from the firm said that the findings of "exhaustive and extensive studies" concluded there was no viable alternative to re-storing the chimneys.
Parkview said they had offered a legally binding undertaking to Wandsworth Council to provide certainty the chimneys will be replaced like for like, meeting the requirements of English Heritage.
Chair of the Battersea Power Station Community Group Brian Barnes said: "Battersea Power Station is nothing without those chimneys, that's what makes it a landmark, there will be nothing to it after that.
"We don't believe making replicas is the same as repairing the structures."
Mr Barnes said they wanted conditions attached to the planning permission, in the form of a £10m bond, to secure the rebuilding or replacement of the chimneys.
"We were told that inspections were made every six months, it can't just be now that these have been found to be a danger, " he said.
Up to 9,000 jobs are to be created with the building of housing, cinemas, restaurants and shops on the 38-acre site.
English Heritage said it had received a planning and listed building consent application for the site.
A statement said it was "keen to ensure that that historic fabric of this Grade II listed national landmark is repaired and restored as soon as possible and that the building as a whole is brought into public use."
It said it had been closely involved in detailed investigations into the structural condition which had been used to inform proposals for the repair and restoration of the building.